Thermal marine propulsion system

ABSTRACT

A mechanical propulsion system of a watercraft includes one or more propeller or impeller units operable to provide thrust for forward cruise. Disclosed herein is a non-mechanical marine propulsion system that utilizes heating-elements installed at submerged-regions of bow and stern of a waterborne watercraft in order to generate a pressure-difference between the bow and the stern by virtue of boiling and displacing surrounding water, and thus provide a net thrust to propel, steer or brake the watercraft. Further, a non-mechanical active roll stabilization system also based on the above concept is disclosed.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present non-provisional patent application claims the benefit of foreign priority to copending Indian non-provisional patent application Ser. No. 202311062497, filed on Sep. 18, 2023 and entitled “THERMAL MARINE PROPULSION SYSTEM”, the complete disclosure of which is expressly incorporated herein by reference in its entirety for all purposes.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not Applicable

THE NAMES OF THE PARTIES TO A JOINT RESEARCH AGREEMENT

Not applicable

INCORPORATION-BY-REFERENCE OF MATERIAL SUBMITTED ON A COMPACT DISC OR AS A TEXT FILE VIA THE OFFICE ELECTRONIC FILING SYSTEM (EFS-WEB)

Not applicable

BACKGROUND OF THE INVENTION Field of the Invention

The invention generally relates to marine propulsion systems and, more particularly, but not exclusively, to non-mechanical marine propulsion systems.

Description of the Related Art Including Information Disclosed Under 37 CFR 1.97 and 37 CFR 1.98

Typically, watercrafts propel by a thrust generated by mechanical systems consisting of an electric motor or an internal combustion engine driving a propeller, or less frequently, in pump-jets, an impeller.

Mechanical active roll stabilization systems produce a torque to oppose roll of a waterborne watercraft by moving masses like anti rolling tanks and active moving weight or by using control surfaces like active fins by means of power.

The mechanical systems are bulky, unreliable and expensive. Moreover, drag between a cruising watercraft and surrounding water limits maximum-speed, maneuverability and fuel-efficiency of the watercraft.

SUMMARY OF THE INVENTION

Accordingly, it is a general purpose and primary object of the present invention to provide a non-mechanical system for marine propulsion via pressure-difference. The system comprises heating-elements symmetrically installed at submerged-regions of bow and stern of a waterborne watercraft, wherein hot-sides of the heating-elements are configured to boil water around the submerged-regions. The resultant steam-filled regions around the heating-elements are at a lower-pressure than water in which the watercraft floats. Thus, activating the heating-elements installed at the bow and deactivating the heating-elements installed at the stern generates a steam-filled low-pressure region ahead of the bow and a water-filled high-pressure region behind the stern, thus a forward-thrust due to a pressure-difference between the regions propels the watercraft forward, and vice-versa. Also, the watercraft can be steered sideways by application of an asymmetric thrust produced by unequally heating the heating-elements in lateral-halves (left and right) of the submerged-regions.

In one embodiment, a non-mechanical active roll stabilization system is provided that includes one or more fixed-fins attached to submerged-region of hull of the waterborne watercraft, and each of the one or more fixed-fins has two heating-elements joined together at a camber line such that respective hot-sides form two airfoil-surfaces, one of which when heated by a control-unit, displaces surrounding water by boiling and resultant pressure-difference between the airfoil-surfaces produces a torque to counteract roll of the watercraft.

Moreover, the non-mechanical systems are more compact, reliable and affordable than their mechanical counterparts; and the steam-filled region offers lesser drag than water, thus increasing maximum-speed, maneuverability and fuel-efficiency of the watercraft.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is described with reference to the accompanying drawings, wherein:

FIG. 1 is an isometric view showing an illustrative and non-exclusive example of a watercraft in a waterborne situation installed with a thermal marine propulsion system and a thermal active roll stabilization system of the present invention.

FIG. 1A is a supplementary schematic rear view of the watercraft of FIG. 1 showing part of the thermal marine propulsion system installed at stern of the watercraft.

FIG. 2 depicts an exemplary a bottom orthographic view of the watercraft of FIG. 1 steering sideways through water towards left-side.

FIG. 3 is a cross-section view of an illustrative and non-exclusive example of a stabilizing-fin of the thermal active roll stabilization system of FIG. 1 .

FIG. 4 illustrates a rear view of working of the thermal active roll stabilization system of FIG. 1 .

DETAILED DESCRIPTION OF THE INVENTION

The marine propulsion system of the present invention comprises heating-elements, preferably plate-like, each with a hot-side. The heating-elements are symmetrically installed to form or cover regions of bow and stern of a watercraft such that the heating-elements are submerged and respective hot-sides make contact with surrounding water when the watercraft is waterborne. Consider a scenario wherein the heating-elements installed at the bow are activated by a control-unit, thereby causing the respective hot-sides to boil surrounding water and generate a steam-filled region ahead of the bow. The steam filled region is at a lower-pressure than water in which the watercraft floats because the surrounding water gets displaced in form of rising steam upon boiling, thereby leaving behind a partial-vacuum. In the meantime, if the heating-elements installed at the stern are deactivated by the control-unit, then high-pressure region of water behind the stern generates a forward-thrust required to propel the watercraft. Note that, the forward-thrust is proportional to pressure-difference between the high-pressure region and the lower-pressure region, which in turn, is proportional to absolute-value of difference of sum of input-powers to the heating-elements installed at the bow and sum of input-powers to the heating-elements installed at the stern. Conversely, the heating-elements installed at the bow are deactivated and the heating-elements installed at the stern are activated in order to generate a reverse-thrust.

The steam filled low-pressure region offers lesser drag to the watercraft than liquid water and a turbulence resulting from the rising steam has a self-cleaning effect against biofouling.

FIG. 1 is an isometric view showing an illustrative and non-exclusive example of a watercraft in a waterborne situation installed with a thermal marine propulsion system and a thermal active roll stabilization system. The shaded-surfaces depict hot-sides of heating-elements 1 installed at bow of the watercraft and a hot-side of a heating-element of the stabilizing-fin 3 of the thermal active roll stabilization system. Note that, heating-elements 2 installed at stern of the watercraft are completely hidden from view in FIG. 1 , that's why they're shown separately in FIG. 1A as the shaded-region.

Moreover, one or more heating-elements in a lateral-half (left or right) of the bow and one or more heating-elements in an opposite lateral-half (right or left) of the stern are heated more than one or more heating-elements in each of respective adjacent lateral-halves so as to generate a net asymmetric thrust that steers the watercraft sideways during cruise or even while being stationary. Note that, turning-radius of the watercraft during cruise is proportional to angle between the asymmetric thrust and longitudinal-axis of the watercraft.

FIG. 2 depicts an exemplary a bottom orthographic view of the watercraft of FIG. 1 steering sideways through water towards left-side, wherein trajectory of the watercraft is illustrated by dashed lines, and wherein a lateral-half of a submerged-region marked by +, . . . , + is hotter and thus experiences a lower-pressure from surrounding steam-filled region than adjacent lateral-half of the submerged-region marked by −, . . . , −.

Finally, a non-mechanical active roll stabilization system of the present invention includes one or more stabilizing-fins fixed to submerged-region of hull of the waterborne watercraft, and each of the one or more fixed-fin has two heating-elements joined such that respective hot-sides form two airfoil-surfaces, one of which when heated by a control-unit on receiving a control-signal from a sensor device, boils surrounding water and forms a steam-filled low-pressure region whilst opposite airfoil-surface being cold remains in contact with water in which the watercraft floats. Hence, a force acting on the stabilizing-fin that is proportional to a pressure-difference between the two airfoil-surfaces produces a counteracting torque opposite to roll of the watercraft, wherein the pressure-difference is proportional to input-power to the heating-element being heated. Note that, magnitude and direction of the torque is determined by magnitude and direction of the force.

FIG. 3 is a cross-section view of an illustrative and non-exclusive example of the stabilizing-fin 3 of the thermal active roll stabilization system of FIG. 1 , wherein hot-side of a first heating-element forms a first airfoil-surface 4, hot-side of a second heating-element forms a second airfoil-surface 5 and the dashed line depicts a camber-line at which the first heating-element and the second heating-element are joined together so as to form the stabilizing-fin 3.

FIG. 4 illustrates a rear view of working of the thermal active roll stabilization system of FIG. 1 , wherein airfoil-surface marked by +, . . . , + is hotter and thus experiences a lower-pressure from surrounding steam-filled region than opposite airfoil-surface surrounded by water and marked by −, . . . , −. An anticlockwise torque acting on the watercraft counteracts a clockwise roll of the watercraft indicated by the circular-arrow and vice-versa, wherein the torque results from a net force acting on the stabilizing-fin 3 due to a pressure-difference between the airfoil-surfaces.

The invention has been described in detail with particular respect to implementations thereof, but it will be appreciated that variations and modifications can be effected within the spirit and scope of the invention. For example, a variety of heating-elements might be employed, including a thermoelectric (Peltier) heat-pump, an electric heater or a fossil-fuel-fired furnace. Further note that the systems of the present invention might be built into hull of the watercraft or installed separately onto surface of hull of an existing watercraft as an upgrade. Finally, while the invention is cast in the environment of watercrafts like ships and submarines, it has other uses, for example, in connection with aircrafts. 

I claim:
 1. A marine propulsion system, characterized in that it comprises: one or more heating-elements each having a hot-side configured to boil water so as to generate a thrust along a normal-vector to the hot-side when in a submerged situation.
 2. The marine propulsion system of claim 1, further comprising a control-unit and a power-supply connected to the heating-elements.
 3. The marine propulsion system of claim 2, wherein one or more heating-elements symmetrically and at least partly form or cover a region of each of bow and stern of a watercraft, wherein the regions are fully-submerged when the watercraft is in a waterborne situation, and wherein hot-sides of the heating-elements make contact with water in which the watercraft floats.
 4. The marine propulsion system of claim 3, wherein the one or more heating-elements in the region of the bow are configured to be heated independently of the one or more heating-elements in the region of the stern so as to generate a net forward or reverse thrust for propelling, reversing or braking the watercraft.
 5. The marine propulsion system of claim 4, comprising plural heating-elements in each of the regions of the bow and the stern, and each of the regions is configured to be asymmetrically heated in lateral directions (left and right) by adjusting input-powers to the plural heating-elements so as to generate an asymmetric thrust for steering the watercraft.
 6. The marine propulsion system of claim 5, further comprising: an active roll stabilization system comprising: a sensor device for detecting undesired watercraft movements (roll) and for supplying thereon based control-signals to a control-unit; the control-unit for controlling one or more stabilizing-elements for the purpose of damping the roll; and the one or more stabilizing-elements being one or more fixed-fins mounted on hull of the watercraft, each of the one or more fixed-fins being characterized in that it comprises a first heating-element forming a first airfoil-shell and a second heating-element forming a second airfoil-shell fixed opposite to the first airfoil-shell at a mean camber-line, wherein the one or more fixed-fins are fully-submerged when the watercraft is in a waterborne situation, wherein hot-side of the first heating-element forms airfoil-surface of the first airfoil-shell and hot-side of the second heating-element forms airfoil-surface of the second airfoil-shell, and wherein the first heating-element and the second heating-element are configured to be heated independently of each other so as to generate a net clockwise or anticlockwise torque for counteracting the roll of the watercraft. 